Before we were missing a space character so the Error Prone args were
not getting passed properly. Do some related minor cleanup.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Refactor**
* Internal assembly of compiler/analyzer invocation arguments was
reorganized for clearer, centralized construction; no behavior change.
* **New Feature**
* Added a new type-annotation handling option to improve
JSpecify/type-annotation processing during analysis.
* **Other**
  * No changes to public API or user workflows.

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settings.</sub>
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

These were showing up in profiles. Note that one of the fixes requires
updating our minimum supported Guava version to 31.1. This was
[released](https://github.com/google/guava/releases/tag/v31.1) in
February 2022, and mostly Guava is backward compatible these days, so
hopefully it's fine for users.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Refactor**
  * Added cached hash/identity values to reduce repeated recomputation.
* Optimized nullness-store merging with faster merge and identity
short-circuit.
  * Builder internals switched to immutable-building semantics.
  * Improved error-message construction formatting.

* **Chores**
  * Bumped Guava dependency to a newer version.
  * Added Guava to the oldest-error-prone test classpath.

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settings.</sub>
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

The `GenericMethodTests` class is getting huge so this helps a little.
Also, add a new simple wildcard test to aid when we start working on
#1360.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Tests**
* Reorganized wildcard and generic type inference test cases into a
dedicated test class for improved organization and maintainability.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

…ESTION level (#1365)

Fixes #1363. What we really want to do is ship this check in a disabled
state, but I don't immediately see a way to do that. So, as a
workaround, don't emit matches when the check is run at the `SUGGESTION`
level.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Bug Fixes**
* The RequireExplicitNullMarking checker now respects severity level
configuration and no longer produces diagnostic reports at the default
SUGGESTION level, reducing unnecessary noise in build outputs.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

These methods are called very frequently. Previously these methods
operated on `Stream`s, but that was causing overhead visible in
profiles. Switch them to use `Iterator`s and a callback `Predicate`.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Refactor**
* Consolidated annotation-checking logic by introducing a centralized
utility method to streamline multiple annotation-matching operations
into a single, reusable component.
* Replaced stream-based checks with explicit iteration for improved
performance and code consistency across annotation-checking operations.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Fixes #1364 

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Documentation**
* Enhanced diagnostic messages with improved formatting and clearer
scope identification.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Documentation**
* Added a Version 0.12.14 entry to the changelog and preserved prior
entries.

* **Bug Fixes**
* RequireExplicitNullMarking is now disabled by default, fixing related
configuration issues.

* **Chores**
* Applied performance optimizations and general maintenance
improvements.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Yuxin Wang <[email protected]>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>